Field
Exemplary embodiments of the present disclosure relate to apparatus and methods for making extrusion dies, more particularly, to apparatus and methods for machining cavities in the manufacturing of honeycomb extrusion dies.
Discussion of the Background
After-treatment of exhaust gas from internal combustion engines may use catalysts supported on high-surface area substrates and, in the case of diesel engines and some gasoline direct injection engines, a catalyzed filter for the removal of carbon soot particles. Porous ceramic flow-through honeycomb substrates and wall-flow honeycomb filters may be used in these applications.
Extrusion dies may be used in manufacturing ceramic honeycomb bodies. Conventional extrusion dies for forming ceramic honeycomb bodies (cellular ceramic products) typically have a series of holes on one side of a metal plate intersecting a series of slots, forming pins, which can have various geometric cross sections such as squares, hexagons, or the like on the opposite side of the metal plate. In order to form the cellular ceramic products, raw material, i.e. batch, is pushed into the hole side of the metal plate and exits the slot side of the metal plate, forming the cellular shape by being extruded through the slots and around the pins.
A variety of machining methods can be used to create this tooling geometry, depending on dimensions and design of the extrusion dies. For the machining of the holes, drilling, twist drilling, gun drilling, and shape tube electrolytic machining (STEM) may be used. For the machining of the slots, abrasive wheel grinding, wire electrical discharge machining (wEDM), wheel slitting and/or plunge electrical discharge machining (pEDM) may be used. After machining, the surfaces of the extrusion dies may be coated with a wear resistant material to improve the life of the extrusion dies.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure and therefore it may contain information that does not form any part of the prior art nor what the prior art may suggest to a person of ordinary skill in the art.